1. Field of the Invention
The present invention relates to a liquid crystal display device, particularly, to a liquid crystal display device of a horizontal electric field type so-called IPS (In-Plane Switching) type, and more specifically to an antistatic structure for a liquid crystal display panel housed in a panel frame.
2. Description of Related Art
Active matrix type liquid crystal display devices which use an active element represented by a thin film transistor (TFT) come in to widespread use as various display devices because of features that they are thin and light in weight and in view of high image quality. The display type of the liquid crystal display device is mainly classified into the following two types.
One of them is the type of displaying an image by interposing liquid crystal between two substrates each formed with transparent electrodes, operating the liquid crystal with voltage applied to the transparent electrodes, and modulating light having passed through the transparent electrodes and incident on a liquid crystal layer. Many products that are currently widespread adopt this vertical electric field type.
The other is the type which is referred to as a “horizontal electric field type” or “In-Plane Switching (IPS) type”. A liquid crystal display panel of the IPS type displays an image by generating an electric field parallel to a substrate surface at least a portion between a pixel electrode and a counter electrode, driving liquid crystal with the electric field, and modulating light passing through a liquid crystal layer. This type has a feature that its view angle is remarkably wide. The feature of an active matrix type liquid crystal display device adopting the IPS type has been described in JP-T-5-505247, JP-B-63-21907, and JP-A-6-160878.
This kind of liquid crystal display device generates an electric field parallel to a substrate surface in order to drive liquid crystal between a color filter substrate and an active matrix substrate which are arranged so as to face to each other. Therefore, in order to stabilize the potential of a surface of the color filter substrate, a transparent conductive film such as of ITO is formed on the entire surface of the color filter substrate on a display surface side, a conductive tape or conductive paste is bonded to a part of the transparent conductive film at the periphery part of the color filter substrate on the display surface side, and a conductive frame is covered, thereby establishing an electrical connection (conduction). As a result, the conductive frame is grounded via another conductive frame or by conducting to a final product.
However, since the thus configured liquid crystal display device uses the conductive tape or conductive paste for the conduction between the conductive frame and the color filter substrate, the number of constituent members and the number of mounting steps (operations) therefor increase, resulting in a problem that the manufacturing cost is high.